Embodiments of the present invention as exemplarily described herein relate generally to apparatuses for providing aerosol samples and to methods of providing aerosol samples. More particularly, embodiments of the present invention relate to apparatuses and methods capable of transporting aerosol samples to an analysis system with increased efficiency and reduced fractionation.
Analysis systems, such as mass spectrometry (MS) systems, optical emission spectrometry (OES) systems and the like, can be used to analyze the composition of a target material. Often, a sample of the target material is provided to an analysis system in the form of an aerosol. As is known in the art, an aerosol generally characterized as a colloid suspension of solid and possibly liquid particles in a gas. The aerosol is typically produced by an aerosol producing apparatus, entrained by a flowing carrier gas and transported to the analysis system as a sample via an aerosol transport conduit. Conventional aerosol transport conduits can be bent to enable the aerosol producing apparatus to produce multiple samples from different locations of a target material to be analyzed at an analysis system. Thus, aerosol transport paths defined by conventional aerosol transport conduits are non-linear. Due to the non-linearity of conventional aerosol transport paths, the aerosol experiences fractionation as it is transported from the aerosol producing apparatus to the analysis system. As is known in the art, fractionation occurs when particles of different elements, isotopes, size and/or geometry within the aerosol become centrifugally separated as the direction along the aerosol transport path changes. Due to the effects of fractionation, the compositional analysis performed by the analysis system may not accurately correspond to the actual composition of the aerosol produced by the aerosol producing apparatus. Bends within conventional aerosol transport paths can also cause the aerosol transport velocity to vary along the length of the transport path and also vary at different locations within the aerosol transport conduit adjacent to a bend. Such non-uniform transport velocities can cause, among other deleterious effects, agglomeration of particles within the aerosol. As a result, relatively small particles within the aerosol undesirably agglomerate to form larger particles, which tends to decrease the overall transport efficiency of the aerosol along the along the aerosol transport path.
Conventional aerosol transport conduits can also be made flexible to enable the aerosol producing apparatus to produce multiple samples from different locations of a target material to be analyzed at an analysis system. However using flexible aerosol transport conduits can cause the compositional analysis performed by the analysis system to undesirably change depending on the location of the target material from which the aerosol was generated. To reduce undesirable variability of compositional analyses induced by a flexible aerosol transport conduit, the flexible aerosol transport conduit is generally provided as tube roughly a few meters in length. Thus, any movement between opposite ends of the flexible aerosol transport conduit result in a reduced amount of bending between the opposite ends of the flexible aerosol transport conduit. Due to the relatively long length of such aerosol transport conduits, however, the aerosol transport time within the conduit can be undesirably increased. As a result, relatively small particles within the aerosol undesirably agglomerate in a similar manner as described above.
In addition, flexible or bent aerosol transport conduits are conventionally made of a plastic material that can be permeable to atmospheric gases. As a result, atmospheric gases can become undesirably entrained with the aerosol as it is transported through the aerosol transport conduit and cause problems with compositional analysis of the aerosol (e.g., due to formation of interferences and high backgrounds).